In the discussion that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art against the present invention.
Tools of the above-related kind are used to mill, by cutting or chip removing machining, workpieces of metal, such as steel, aluminium, cast iron, etc. They may also be used for the milling of composite materials.
In some applications, it is necessary to supply a flushing fluid to the individual chip channels in which the milling inserts are mounted, foremost in order to, as fast as possible, carry away the chips that are removed from the workpiece, but often also to cool the milling inserts and the surroundings thereof. When a chip-evacuating effect as well as a cooling effect is desired, some form of liquid is usually used, e.g., water or oil emulsions. If the fluid only should have a chip-removing effect, the same advantageously may be gaseous, preferably in the form of air. For this purpose, the present milling tools are constructed with an internal, suitably centrally situated, bore that forms a main duct through which the fluid can, from a storage container in or adjacent to the driving machine, be fed up to the head, where it, in one way or the other, is distributed outward to the peripherally situated milling inserts. In respect of the supply of fluid to the milling inserts, the present tools may be divided into two main categories, a first one of which makes use of a chamber that is formed in the front part of the head and to which the fluid is fed via the main duct in order to then be distributed outward individually to the milling inserts via individual, internal branch ducts, most often in the form of drilled holes or bores. The second category of tools makes use of a nozzle that is arranged in the front part of the head and, via a plurality of small nozzle holes, distributes the fluid outward to the milling inserts in an indifferent, shower-like flow. A disadvantage of the latter type of tools is that the initially pressurized fluid quickly loses its pressure as soon as the same has been flushed out through the nozzle, and then has a comparatively long distance to travel before it reaches up to the chip channel. Therefore, the rinsing of the milling inserts and the chip channels becomes fairly mediocre.
By U.S. Pat. No. 6,450,738 and WO 2007/085281, milling tools are previously known belonging to the category that distributes the cooling liquid in an external, indifferent flow, more precisely from a central nozzle via peripheral slots adjacent to the individual chip channels and milling inserts. Because of that, no distinct jets of appreciable pressure via internal branch ducts can be provided.
In SE 517817, there is shown a milling tool that, per se, includes a form of branch ducts intended to individually distribute cooling liquid to the individual milling inserts. However, in this case, the branch ducts are in the form of open grooves in the front surface of the milling cutter head and no sealing cover at all is included in the tool.